--[[
Title: math lib funcions
Author(s): http://www.dialectronics.com/Lua/, see below, ported to NPL by LXZ
Date: 2008/4/22
Desc: 2013.11.21: if LuaJit is found, use the luajit version. it is as fast as in C++
see http://lua-users.org/lists/lua-l/2010-03/msg00757.html
Use Lib:
-------------------------------------------------------
NPL.load("(gl)script/ide/math/bit.lua");

The following is fast and implemented in C++
-------------------
mathlib.bit.bnot(n) -- bitwise not (~n)
mathlib.bit.band(m, n) -- bitwise and (m & n)
mathlib.bit.bor(m, n) -- bitwise or (m | n)
mathlib.bit.bxor(m, n) -- bitwise xor (m ^ n)
mathlib.bit.rshift(n, bits) -- logical right shift (n >> bits), padding with 0
mathlib.bit.lshift(n, bits) -- logical left shift (n << bits), padding with 0
mathlib.bit.cast(a)        cast a to the internally-used integer type
mathlib.bit.arshift(a, b)  returns a shifted arithmetically right b places
mathlib.bit.alshift(a, b)  returns a shifted arithmetically left b places

The following is SLOW and implemented in lua
--------------------
-- These functions are big-endian and take up to 32 bits
mathlib.bit.Hex2Bin
mathlib.bit.Bin2Hex
mathlib.bit.Hex2Dec
mathlib.bit.Dec2Hex
mathlib.bit.Bin2Dec
mathlib.bit.Dec2Bin

-- These functions are big-endian and will extend to 32 bits
mathlib.bit.BMAnd
mathlib.bit.BMNAnd
mathlib.bit.BMOr
mathlib.bit.BMXOr
mathlib.bit.BMNot
mathlib.bit.BShRight;
mathlib.bit.BShLeft;

-------------------------------------------------------
]]
if(not mathlib) then mathlib={}; end
if(not mathlib.bit) then 
	if(jit and jit.version) then
		-- if luajit is enabled use the jit version, which is faster. 
		mathlib.bit = require("bit");
	else
		mathlib.bit = luaopen_bit() ;
	end
end

local bit = mathlib.bit;

--[[
/*
 * Copyright (c) 2007 Tim Kelly/Dialectronics
 *
 * Permission is hereby granted, free of charge, to any person obtaining 
 * a copy of this software and associated documentation files (the 
 * "Software"),  to deal in the Software without restriction, including 
 * without limitation the rights to use, copy, modify, merge, publish, 
 * distribute, sublicense, and/or sell copies of the Software, and to permit 
 * persons to whom the Software is furnished to do so, subject to the 
 * following conditions:
 *
 * The above copyright notice and this permission notice shall be 
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT 
 * OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR 
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
--]]

local hex2bin = {
	["0"] = "0000",
	["1"] = "0001",
	["2"] = "0010",
	["3"] = "0011",
	["4"] = "0100",
	["5"] = "0101",
	["6"] = "0110",
	["7"] = "0111",
	["8"] = "1000",
	["9"] = "1001",
	["a"] = "1010",
        ["b"] = "1011",
        ["c"] = "1100",
        ["d"] = "1101",
        ["e"] = "1110",
        ["f"] = "1111"
	}



local bin2hex = {
	["0000"] = "0",
	["0001"] = "1",
	["0010"] = "2",
	["0011"] = "3",
	["0100"] = "4",
	["0101"] = "5",
	["0110"] = "6",
	["0111"] = "7",
	["1000"] = "8",
	["1001"] = "9",
	["1010"] = "A",
        ["1011"] = "B",
        ["1100"] = "C",
        ["1101"] = "D",
        ["1110"] = "E",
        ["1111"] = "F"
	}

--[[
local dec2hex = {
	["0"] = "0",
	["1"] = "1",
	["2"] = "2",
	["3"] = "3",
	["4"] = "4",
	["5"] = "5",
	["6"] = "6",
	["7"] = "7",
	["8"] = "8",
	["9"] = "9",
	["10"] = "A",
	["11"] = "B",
	["12"] = "C",
	["13"] = "D",
	["14"] = "E",
	["15"] = "F"
	}
--]]


local function Hex2Bin(s)

-- s	-> hexadecimal string

local ret = ""
local i = 0


	for i in string.gfind(s, ".") do
		i = string.lower(i)
		ret = ret..hex2bin[i]

	end

	return ret
end


local function Bin2Hex(s)

-- s 	-> binary string

local l = 0
local h = ""
local b = ""
local rem

l = string.len(s)
rem = l % 4
l = l-1
h = ""

	-- need to prepend zeros to eliminate mod 4
	if (rem > 0) then
		s = string.rep("0", 4 - rem)..s
	end

	for i = 1, l, 4 do
		b = string.sub(s, i, i+3)
		h = h..bin2hex[b]
	end

	return h

end


local function Bin2Dec(s)

-- s	-> binary string

local num = 0
local ex = string.len(s) - 1
local l = 0

	l = ex + 1
	for i = 1, l do
		b = string.sub(s, i, i)
		if b == "1" then
			num = num + 2^ex
		end
		ex = ex - 1
	end

	return string.format("%u", num)

end



local function Dec2Bin(s, num)

-- s	-> Base10 string
-- num  -> string length to extend to

local n

	if (num == nil) then
		n = 0
	else
		n = num
	end

	s = string.format("%x", s)

	s = Hex2Bin(s)

	while string.len(s) < n do
		s = "0"..s
	end

	return s

end




local function Hex2Dec(s)

-- s	-> hexadecimal string

local s = Hex2Bin(s)

	return Bin2Dec(s)

end



local function Dec2Hex(s)

-- s	-> Base10 string

	s = string.format("%x", s)

	return s

end

-- These functions are big-endian and take up to 32 bits

bit.Hex2Bin = Hex2Bin
bit.Bin2Hex = Bin2Hex
bit.Hex2Dec = Hex2Dec
bit.Dec2Hex = Dec2Hex
bit.Bin2Dec = Bin2Dec
bit.Dec2Bin = Dec2Bin


local function BMAnd(v, m)

-- v	-> hex string to be masked
-- m	-> hex string mask

-- s	-> hex string as masked

-- bv	-> binary string of v
-- bm	-> binary string mask

local bv = Hex2Bin(v)
local bm = Hex2Bin(m)

local i = 0
local s = ""

	while (string.len(bv) < 32) do
		bv = "0000"..bv
	end

	while (string.len(bm) < 32) do
		bm = "0000"..bm
	end


	for i = 1, 32 do
		cv = string.sub(bv, i, i)
		cm = string.sub(bm, i, i)
		if cv == cm then
			if cv == "1" then
				s = s.."1"
			else
				s = s.."0"
			end
		else
			s = s.."0"

		end
	end

	return Bin2Hex(s)

end


local function BMNAnd(v, m)

-- v	-> hex string to be masked
-- m	-> hex string mask

-- s	-> hex string as masked

-- bv	-> binary string of v
-- bm	-> binary string mask

local bv = Hex2Bin(v)
local bm = Hex2Bin(m)

local i = 0
local s = ""

	while (string.len(bv) < 32) do
		bv = "0000"..bv
	end

	while (string.len(bm) < 32) do
		bm = "0000"..bm
	end


	for i = 1, 32 do
		cv = string.sub(bv, i, i)
		cm = string.sub(bm, i, i)
		if cv == cm then
			if cv == "1" then
				s = s.."0"
			else
				s = s.."1"
			end
		else
			s = s.."1"

		end
	end

	return Bin2Hex(s)

end



local function BMOr(v, m)

-- v	-> hex string to be masked
-- m	-> hex string mask

-- s	-> hex string as masked

-- bv	-> binary string of v
-- bm	-> binary string mask

local bv = Hex2Bin(v)
local bm = Hex2Bin(m)

local i = 0
local s = ""

	while (string.len(bv) < 32) do
		bv = "0000"..bv
	end

	while (string.len(bm) < 32) do
		bm = "0000"..bm
	end


	for i = 1, 32 do
		cv = string.sub(bv, i, i)
		cm = string.sub(bm, i, i)
		if cv == "1" then
				s = s.."1"
		elseif cm == "1" then
				s = s.."1"
		else
			s = s.."0"
		end
	end

	return Bin2Hex(s)

end

local function BMXOr(v, m)

-- v	-> hex string to be masked
-- m	-> hex string mask

-- s	-> hex string as masked

-- bv	-> binary string of v
-- bm	-> binary string mask

local bv = Hex2Bin(v)
local bm = Hex2Bin(m)

local i = 0
local s = ""

	while (string.len(bv) < 32) do
		bv = "0000"..bv
	end

	while (string.len(bm) < 32) do
		bm = "0000"..bm
	end


	for i = 1, 32 do
		cv = string.sub(bv, i, i)
		cm = string.sub(bm, i, i)
		if cv == "1" then
			if cm == "0" then
				s = s.."1"
			else
				s = s.."0"
			end
		elseif cm == "1" then
			if cv == "0" then
				s = s.."1"
			else
				s = s.."0"
			end
		else
			-- cv and cm == "0"
			s = s.."0"
		end
	end

	return Bin2Hex(s)

end


local function BMNot(v, m)

-- v	-> hex string to be masked
-- m	-> hex string mask

-- s	-> hex string as masked

-- bv	-> binary string of v
-- bm	-> binary string mask

local bv = Hex2Bin(v)
local bm = Hex2Bin(m)

local i = 0
local s = ""

	while (string.len(bv) < 32) do
		bv = "0000"..bv
	end

	while (string.len(bm) < 32) do
		bm = "0000"..bm
	end


	for i = 1, 32 do
		cv = string.sub(bv, i, i)
		cm = string.sub(bm, i, i)
		if cm == "1" then
			if cv == "1" then
				-- turn off
				s = s.."0"
			else
				-- turn on
				s = s.."1"
			end
		else
			-- leave untouched
			s = s..cv

		end
	end

	return Bin2Hex(s)

end


-- these functions shift right and left, adding zeros to lost or gained bits
-- returned values are 32 bits long

-- BShRight(v, nb)
-- BShLeft(v, nb)


local function BShRight(v, nb)

-- v	-> hexstring value to be shifted
-- nb	-> number of bits to shift to the right

-- s	-> binary string of v

local s = Hex2Bin(v)

	while (string.len(s) < 32) do
		s = "0000"..s
	end

	s = string.sub(s, 1, 32 - nb)

	while (string.len(s) < 32) do
		s = "0"..s
	end

	return Bin2Hex(s)

end

local function BShLeft(v, nb)

-- v	-> hexstring value to be shifted
-- nb	-> number of bits to shift to the right

-- s	-> binary string of v

local s = Hex2Bin(v)

	while (string.len(s) < 32) do
		s = "0000"..s
	end

	s = string.sub(s, nb + 1, 32)

	while (string.len(s) < 32) do
		s = s.."0"
	end

	return Bin2Hex(s)

end


-- These functions are big-endian and will extend to 32 bits

bit.BMAnd = BMAnd
bit.BMNAnd = BMNAnd
bit.BMOr = BMOr
bit.BMXOr = BMXOr
bit.BMNot = BMNot

bit.BShRight = BShRight;
bit.BShLeft = BShLeft;


